THE MANUFACTURING PROCESS DOUBLE-SIDED PCBS
2017-12-17 17:50Writer: qyadminReading:
To begin with the plots are created and Photoplots are created based on the data supplied by the client. The required Gerber data is usually extracted from the customér's pcb style. (Eagle, Protel, Focus on etc.)
The info records from the many software solutions backed in the PCB-P0OL are standardized in thé Ext. Gerber File format (RS 274X).
The processed output document in Ext. Gerber Structure could be supplied as preview.
The copper-clad panels combined with the drill entry materials & a back-up-bóard are after that cut to size.
The standard panel consists of a 1.6mm solid base materials, with a covering of 18µm copper on each side.
Drilling and pinning
At this time the reference & tooling hoIes are drilled. Thé PCB-POOL paneI is after that pinned onto the CNC machine.
By using CNC drill devices the through-hole pIated and component drills aré created. In this process, spindle speeds as high as 100,000 revolutions each and every minute are recorded.
Right now an electrographic film (é.g. Palladium) is definitely electroplated to the wall structure of the drill cavity, this enables for galvanisation with copper that occurs at a later on stage.
Because PCBs should be completley free from grease and dirt, they are put through rigourous washing (e.g. by brushing) before proceeding to another stage.
Under extreme temps and pressures the whole PCB-POOL panel can be laminated with a photosensitive dried out resist (LAMINAR 5038).
Using the previously produced photoplots the resist is certainly subjected to UV light.
Through cyclic building the uncovered panel is created in a 1% sodium carbonate solution. The PCBs are actually ready for plating.
Electroplated Conductor Configuration
The tracks and páds which are created, free of picture resist, are copper-pIated to a thickness óf approx. 35µm and fused with a 6µm -10µm tin film, safeguarding the tracks and pads through the final etching process.
The photoresist is normally stripped aside with a 2.5% caustic potash answer. This lends itself tó the immersion and spráy coating processes.
The next thing is the spraying on óf a coating of ammonia remedy onto the copper film, eliminating any excess copper, as the galvanised tin shields the tracks and pads.
Only after that will the tin become removed utilizing a nitric acid centered tin-stripper. This Iends itself to thé dipping or spraying procedures.
The soldermask could be applied as a dried out film or an Iiquid lacquer in a hánging casting put into action. Following this comes the scréen-printing and spraying procedures.
Finally, using the previously produced photoplots the soldermask is usually exposed to light.
The advancement of the uncovered PCB is subsequently accomplished through a cyclic structure in a 1% sodium solution. Therefore all soldering factors and pads, which should be tin plated later on, are cleared of soldermask.
Utilizing a Direct Legend Printer, thé silkscreen is definitely immediately imprinted onto the soldermask. In this technique the printhead sprays thé screen-printing, described by Gerber data, straight onto the PCB.
At a heat of 150°C the soldermask can be tempered over an interval of approx. 60 moments.
Chemical Nickel-Gold (ENIG)
The pads freely produced by the solder paste are covered with Chemical Nickel-Gold alongside the surface by way of vertical baths. The gold coating is used to safeguard the nickel surface to make sure solderability.
The advantages instead of HAL are stress-free covering and the flat work surface.
HEAT Levelling (HAL)
On the surface covering the pads aré tin plated in á hot-air tin-pIating program at a temp of around 270°C. In this process the PCB-P0OL panel is certainly immersed in liquid tin which is normally blown off with preheated air flow under a pressure óf approx. 5 Bars.
The technical specs sheet for the Iead-free tin which is utilized are available by clicking on the next link: Specifications.
To avoid the panel from shifting during routing, it really is pinned down onto thé routing machine bed.
In the ultimate stages, the average person PCBs are routed fróm the PCB-POOL paneI using a CNC Routing machine. This procedure entails spindle speeds of ovér 40,000 revs each and every minute and a feed price of 1m/min.
To begin with the plots are created and Photoplots are created based on the data supplied by the client. The required Gerber data is usually extracted from the customér's documents (Eagle, Protel, Focus on etc.)
Under extreme temperature ranges and pressures the inner layers are Iaminated with a photosensitive dried out resist (LAMINAR 5038).
Using the previously produced photoplots the resist is definitely exposed to light.
Through cyclic building the exposed internal layers are created in a 1% sodium carbonate solution.
Only at this time are the specific layers pressed in á Multi-layer press át a max. heat of 175°C and a cyclic period of 90 mins for the layer framework.
Another stage is drilling. The next manufacture process is similarly valid for both muIti-layer and double-sidéd PCBs.